Trough mixer having a dosing arrangement for mixing fibrous materials



Aprll 14, 1970 ENGELS ET AL 3,506,201 I TROUGH MIXER HAVING A DOSING ARRANGEMENT FOR MIXING FIBROUS MATERIALS Failed Dec. 16, 1966 v 5 Sheets-Sheet 1 i n v en Iors. Kama/e 0/9/16 A/VO April 14, 1970 I NG L ET AL 3,506,201

TROUGH MIXER HAVING A DosING ARRANGEMENT FOR MIXING FIBROUS MATERIALS Filed Dec. 16, 1966 5 Sheets-Sheet 2 Inventors.-

April 14, 1970 EN Ls ET AL THOUGH MIXER HAVING A DOSING ARRANGEMENT Filed Dec. 16, 1966 FOR MIXING FIBROUS MATERIALS 5 Sheets-Sheet 4 v.0 3 Ms Z f P 1 4 8 m N. L M n u n n n n Q 2: 12: M Q? R o o o \I m o o o I m uow w 3 3 Q? a E L c m r L 5 u =3 m3 m a 31a 2% 1 g 3 n z. 7 K21 v, r Y 4 a z a a a: 2 2 2 2 =2 3 2 2 5 3 R 3 .2 2 m9.

April 14, 1970 K. ENGELS ET AL 3,506,201

I TROUGH MIXER HAVING A DOSING ARRANGEMENT FOR MIXING FIBROUS MATERIALS Filed Dec. 16, 1966 5 Sheets-Sheet 5 3,506,201 TROUGH MIXER HAVING A DOSING ARRANGE- MENT FOR MIXING FIBROUS MATERIALS Kaspar Engels, Mannheim-Waldhof, and Wilhelm Schneider, Ludwigshafen (Rhine), Germany, assignors to Draiswerke GmbH, Mannheim-Waldhof, Germany, a

firm

Filed Dec. 16, 1966, Ser. No. 602,295 Claims priority, applicatigg 9(:r eszvrmany, Dec. 17, 1965,

Int. (:1. B2c 13/10 US. Cl. 241-42 6 Claims ABSTRACT OF THE DISCLOSURE BACKGROUND OF THE INVENTION The present invention relates to mixing apparatus for mixing materials, such as fibrous materials with different binding agents and/or dye stuffs, hardening agents and other additives.

More in particular, the invention concerns a trough mixer with a nozzle arrangement where fibrous or chiplike substances, such as wood, paper, coco, hemp, cloth and the like are mixed with liquid or powdery binding agents, with components of liquid or dry coloring or dye substances, water, a hardening agent and other additives in order to produce from such a mixture the desired end products, for example, by pressing as into the form of plates.

SUMMARY OF THE INVENTION Different types of trough mixers are known for applying glue to wood fibers or chips or the like. Thus there are continuously and interruptedly operating trough mixers in which one or more stirring devices initiate movement of the fibrous or chip-like material in more or less fluifed condition and where the binders and additives in liquid or powder form are sprayed onto the fiuffed mass or introduced in any other different manner. Embodiments have also been proposed where more rapidly running mixing tools force the wood chips to follow correspondingly greater paths of projection. Machines of this type require additional equipment to return the chips to the casting or throwing tools.

Machines of this type for applying glue to wood chips, particularly for applying glue to and moistening fibrous substances are subject to the shortcoming that the fibrous substances to be coated or moistened tend to mat. Irnmediately after or during the addition of the binders, resins or the like the chip-like or fibrous substances mat to form lumps which have different proportions of binder material from the core outwardly and which do not dissolve or break up as a result of the spreading or pressing that follows the mixing operation. Therefore, the end products are not consistent as to quality and appearance.

It is therefore an object of the invention to prevent the clumping or balling of the mix in the mixing trough as much as possible or to break up clumps which form in the mixing trough.

The problem is solved by providing a trough mixer latent O ice having a blow nozzle arrangement for mixing fibrous substances preferably with liquid binding agents, if desired also with dye substances and other additives, comprising a mixing trough through which the fibrous or chiplike material is passed by means of rotating mixing, overturning and casting elements, or by inclining the mixing trough, While continuously absorbing the additives, which trough, in accordance with the invention is subdivided by screening devices holding back the clumps, and balls that form during the mixing and where cutting wings or arms for breaking up the clumps and balls of mix are disposed ahead of the screens. It is advantageous in this connection to operate the trough mixer continuously and to subdivide it into a plurality of chambers by means of a plurality of screening devices having cutting arms or wings located ahead of them. The screening devices serve the purpose of holding back the lumps or balls of mix formed in the individual chambers from the flow of the remaining material until they are broken up or dissolved by the rotating cutters.

The cutting arms or beaters in accordance with the invention may be disposed on the shaft means for the mixing, over-turning and casting members and like the screening devices they may be mounted in mixing troughs of conventional construction. In order to achieve more rapid comminution of the clumps or balls of mix, it is particularly advantageous to drive the cutting arms at a high number of revolutions. For this purpose the cutting arms may be mounted on separate shafts, hubs or the like. In a particularly advantageous manner the cutting arms may simultaneously serve as mixing arms. If the mixing trough is subdivided into a plurality of separated chambers by the screening devices, it is necessary to provide supply nozzles for the binding agents for each chamber, and mixing, turning and casting arms or members adapted to the prevailing degree or condition of the mix in the individual chambers.

In accordance with a further feature in accordance with the invention the rotating cutting wings cooperate with stationary counter cutters disposed immediately before the screens. This makes it possible to obtain an increase in the passage or production of mix material. In order to avoid balling or clumping of the mix material to a considerable extent, and to impart precomminution to the lumps being formed, a further feature of the invention provides for the arrangement of cutters ahead of the screens alongside the cutting arms, which rotate at the same velocity as the cutting arms.

In a modified embodiment where the mix material is passed through by inclination of the trough, the invention provides for the arrangement of screening devices in the form of tunnel shaped screens having their points downwardly directed in the inclined or vertically disposed mixing trough and for cutting arms mounted on a shaft at a fixed distance ahead of the screens and parallel thereto.

In a particularly advantageous manner the screens are arranged in the mixing trough in such a way that they may be displaced to permit adjustment of the cutting flowever, a further embodiment in accordance with the invention is particularly advantageous, where the mixing trough is subdivided by cylindrical screens with separating walls disposed With their axes perpendicularly to the mixing trough, which hold back the balls and lump formed during mixing and in which these retained products are broken up by beating and/ or cutting tools. For this purpose the arrangement may be such that evading spaces are provided above the shaft of the cutters or beaters, the borders of which are defined by stationary walls arranged in the mixing trough. It is advisable to select the width of these evading spaces smaller than the diameter of the cylinder screen associated therewith.

Air balancing apertures are advantageous in these walls in order to obtain a balance of pressure in the individual mixing spaces.

This manner of installing cylinder screens disposed at right angles relative to the axis of the mixing trough makes it possible to provide in a simple manner for displacing or moving the screens like chests.

Finally, it is possible to provide additional mixing devices below the cylinder screens transversely of the axis of the trough, thereby preventing dead spaces in these locations.

BRIEF DESCRIPTION OF THE DRAWINGS Further details, features and advantages of the invention will become apparent from the following description with reference to the accompanying drawings which illustrate different embodiments of a trough mixer equipped with the screens and comminuting tools according to the invention, and in which,

FIG. 1 shows a sectional view of continuously operating trough mixer in horizontal position,

FIG. 2 is a sectional view taken along line IIII in FIG. 1,

FIG. 3 is a sectional view of a mixer in accordance with the invention arranged vertically,

FIG. 4 is a sectional view taken along line IVIV in FIG. 3,

FIG. 5 is a longitudinal sectional view of a further embodiment of a trough mixer, and

FIG. 6 is a sectional view taken along line VV in FIG. 5.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The continuously operating trough mixer for applying agglutinant and other substances to fibers illustrated in FIG. 1 comprises a trough 1 and a hood 2 which is provided with nozzles 3. The fibrous material is introduced through a funnel 4 and leaves the mixer through a discharge aperture 5. A mixing assembly is arranged in the mixing trough which consists of a shaft 6 equipped with mixing arms 7. The mixing shaft 6 is driven by way of a disk 8 and is journalled in bearings 9. In accordance with the invention the trough of the mixer 1 is subdivided by screening devices such as screen walls 10. In front of these screen walls 10 cutting tools 11 are arranged which rotate at high speed and are also adapted for mixing which cooperate with stationary counter cutters 12. The cutting arms 11 are advantageously mounted for adjustment on a hub 13 which is driven by a motor 27 by way of a belt pulley 14 and a belt 15.

Additional freely rotating cutting arms 16 may be arranged on the hub 13. The surfaces of the screen walls 10 may be extended into the area of the hood 2 by means of screen 17 in a manner that the mixing trough defined by the trough mantle 1 and the hood 2 is subdivided into chambers. The mixing arms 7 are advantageously so arranged that a small thrust is applied to the clumps or balls of mix in the direction of the screens 10.

FIG. 2 is a cross section of trough 1 with the hood 2 and nozzles 3. A hub or sleeve 13 is journalled on the mixing shaft 6 which carries the cutting arms 11 and is driven by means of a V-belt by the motor 27 at a higher number of revolutions than the shaft of the mixing assembly. The cutting arms 11 cooperate with the stationary cutters 12 mounted closely to the screen 10. The screen 17 closes the free space underneath the hood 2.

In contrast to the embodiment in accordance with FIGS. 1 and 2 which illustrate a horizontal trough mixer where besides the cutters a mixing means of conventional construction operates at a low number of revolutions, FIGS. 3 and 4 illustrate a particularly advantageous embodiment of a vertical trough mixer. Screens 21 which are preferably funnel shaped are fixedly mounted in the trough 20. The screens may, however, be also arranged horizontally or cylindrically in the trough 20. With the cylindrical embodiment special feed back means for the fibrous material would then be needed. A shaft means such as a mixing shaft 22, axially disposed in the trough, carries cutting devices or arms 23 which are secured to the shaft 22 by means of a hub 24. The cutting arms 23 are preferably mounted parallel to the screens 21 and scan them at a relatively small distance. It is furthermore possible to arrange additional counter cutters 26 between the cutting arms and the screens. The shaft with the cutting arms 23 rotates at a relatively high mumber of revolutions, for example at 600 rpm. with a trough diameter of 700 mm. Especially with the vertical trough arrangement the cutting arms 23 serve simultaneously as mixing arms for the mass of fiber mix present at any particular time between two screens 21, which as indicated by the arrow runs into the trough mixer from the top and upon passing through the individual screens leaves through the bottom. It is, of course, also possible to feed the fiber mass into the second or third chamber of the trough mixer, depending on the finess of the material. In a particularly advantageous manner the screens 21 may be arranged for adjustment of height on the wall 20 of the trough by means of screws or the like (not shown) to permit of adjusting the cutting gap that is most suitable for the fiber mass supplied at any particular time. The nozzles 25 are so arranged that they spray in through the wall of the trough 20 laterally into the spaces between two screens. The conical arrangement of the screens also provides the advantage that the centrifugal forces resulting from the effect of the cutting arms favorably influence the draft on the balls of fiber material and binder and that thereby the output or efiiciency of the screen is essentially increased. Beyond that, the inclined arrangement of the screens assures of pure overturning of the fibrous material between two screens without development of a closed ring formation.

FIG. 4 shows a horizontal section of the vertical trough mixer with the trough mantle 20, the cutting arms 23 and the counter cutters 26 in accordance with FIG. 3. The screen 21 is arranged at a short distance behind the counter cutters. The cutting arms 23 are arranged, preferably adjustably, on a hub 24. The journalling of the mixing shaft 22 and its driving means is not illustrated in FIG. 4. The cutting arms 23 are set up for pulling cutting as shown in FIG. 4, but other forms of cutting arms may also be employed.

The mixer in accordance with FIGS. 5 and 6 comprises the trough 28 in which the mixing shaft 29 with mixing arms 30 is mounted. The mixing shaft is driven by way of the flange 31 of a pulley by means of drive means which are not illustrated in detail. The mixing shaft is journalled in bearings 32 and 33. The upper part of the trough 28 is closed by means of a hood 34, which in turn is provided with nozzles 35 that serve, for example, for supplying a binding agent. The fibrous material is fed into the trough 28 by means of the funnel 36 and leaves the mixer through the outlet opening 37.

Two separating 'walls 38, 38a are provided in the trough which subdivide the mixer into three compartments A, B, C. The fibrous material supplied to the mixer through funnel 36 is moved in the trough A by the mixing tools 29, 30 and is sprayed through the first three nozzles 35. In accordance with the amount or quantity of fibrous material fed into the funnel 36, fibrous material partially glue coated by the nozzles 35 moves in the direction of the arrow 39 into the first screening means, cylinder screen 40, which, as shown in the drawing, is in the form of a semi cylinder. The fibers which enter the screen area at 39 are completely disentangled here by the beating and cutting device 41. This means that objectionable lump formations are destroyed in the cylinder screens 40. Differences in the supply of lumps not completely dissolved in the passing material are given an opportunity to move upwardly into the escaping space a so that they can be seized repeatedly by the beating tools 41.

The disentangled fibers, i.e. the destroyed lump formations then pass through the screen 40 and reach the chamber or space B.

Since no mixing arms which are disposed radially with respect to the mixing shaft 29 can be located below the screen 40, care must be taken that the fibers which leave the screen 40, are again supplied to the mixing arms 30 by means of a special transversely disposed mixing assembly 42 so that they may be moved in chamber B in a similar manner and sprayed further with glue by additional nozzles 35.

The cutter or beater mechanism 41 running at high speed circulates air in a large volume which without special measures would be forced through the screen 40 in the direction of chamber B and would thus be driven in the direction of the outlet of the mixing trough. Arrangements are therefore made that the spaces a, a are provided at their upper ends in walls 45 and 45a with air balancing apertures 43 toward space A and 44 toward space B.

The disentangling operation described above is repeated in this mixing trough at 38a, 39a, 40a, 42a. A disentangling mechanism of the same construction and function is also provided at the outlet end of the mixer. An overflow wall 38a is provided and the direction of flow of the glue coated fibers into the screen space with the screen 40b and the beating mechanism 41b rotating there in is indicated at 39b. Also there it is possible for excess material or lumps to reach an evading space a", which is separated by the wall 45b from the inflow 39b. The evading space a" in this case is in communication with the mixing space or chamber C only by air balancing apertures 43b. The fully, finally and most evenly glue coated fibers which are discharged through the screen 40!) leave through the outlet opening 37 to be treated further. The evading spaces a, a, and a" may conveniently be provided with additional nozzles 35a, in order to utilize also that area for glue distribution.

It has been found that in the treatment of fibrous material with glue a certain amount of clogging of the screens is unavoidable. The solution of this problem proposed here provides for the effective coating of such fibrous material with glue that the screens are slidable sections as illustrated in FIG. 6 of the drawings. Also here the mixing trough is identified at 28, the mixing shaft at 29 and the mixing arms at 30. The mixing trough is covered at the top by the hood 34 where gluing nozzles 35a are arranged. Above the shaft 29 the beater shaft 41 is disposed rectangularly relative to the axis of the trough, which sweeps over the cylindrical screen 40. The beater shaft 41 is driven by the motor 46 by way of pulleys 47 and 48. The screen 40 is secured to a frame 49 which is twice as wide as the actual mixing trough. This frame is suflicient to accommodate two screen lengths 40, 40'. The screen 40 as shown in FIG. 6 is in active position. The screen 40' can be cleaned in this position or may be exchanged. As soon as the screen 40 indicates clogging, which is normally reflected by the power consumption of the motor 46, the frame 49 is displaced in the direction of the arrow Y, whereupon the frame moves with the screen 40 to the position indicated in dot and dash line 49, while screen 40' arrives in operating position and the screen 40 is exposed for cleaning or exchanging. Thus the exchanging of the screen can take place without interruption in the operation.

Inside the hood 34 there can also be seen passage apertures 44 for the balancing of the air between chambers A and B, for example.

FIG. 6 also shows in combination with FIG. 5 that one mixing mechanism 42 is disposed below the cylinder screen 40 and that it is driven by the motor 50 by way of pulleys 51 and 52.

Having now described our invention with reference to the embodiments illustrated in the drawings, but what we desire to protect by letters patent is set forth in the appended claims.

We claim:

1. Trough mixer for mixing fibrous materials, for example wood, paper, coco, hemp, cloth fibers, with binding agents, especially liquid agents or other additives, said mixer comprising, a mixing trough, a nozzle arrangement disposed in spraying relation to said trough, a main mixing shaft extending longitudinally of said trough, arms for mixing, overturning and casting material mounted on said mixing shaft for rotation in said mixing trough, at least one screening device disposed generally transversely of and subdividing said trough, said at least one screening device. being in the form of a semi-cylinder, and separating walls extending laterally of said at least one screening device, downwardly before the forward end of the screening device and upwardly adjacent the rearward end thereof, and a working mechanism comprising a shaft with radially extendings arms disposed transversely of said main mixing shaft proximate said at least one screening device, operative to disentangle balls and lumps formed in the material being treated.

2. Trough mixer in accordance with claim 1, where evading spaces are provided above said working mechanism, said spaces being defined by downwardly extending walls.

3. Trough mixer in accordance with claim 2, where the width of said evading spaces is smaller than the diameter of said semicyclinder screens.

4. Trough mixer in accordance with claim 3, where apertures for balancing the air pressure in adjacent chambers are provided in said separating and downwardly extending walls.

5. Trough mixer in accordance with claim 4, where a frame extends transversely across and laterally from said mixer, said frame supporting two similar screens and being slidably movable with said screens to permit movement of one screen out of the mixer for cleaning.

6. Trough mixer in accordance with claim 4 including a further mixing mechanism extending transversely of said mixer below said screening device.

References Cited UNITED STATES PATENTS 744,382 11/1903 Moor 24l69 X 2,019,454 10/1935 Larsen 24l69 2,291,038 7/1942 Hazle 241-79.2 X 2,672,075 3/ 1954 Fraser 24169 X 2,943,800 7/1960 Wultsch 24142 3,249,310 5/1966 Willems 24178 X FOREIGN PATENTS 861,048 4/ 1952 Germany.

ROBERT C. RIORDON, Primary Examiner D. G. KELLY, Assistant Examiner US. Cl. X.R. 241-78, 98, 154 

